When performing different kinds of sports, for example snowboarding, skateboarding, skiing, cycling, motorcycling, etc., it is not unusual that the practiser is subjected to accidents resulting in fractures of the bones in the forearm or in the hand. The reason for this is often that the practiser, for example during a fall, as a reflex opens his hand and perhaps stretches his fingers out to break his fall with the flat of the hand. The hand and/or the fingers will thereby form relatively long lever arms and are easily broken by heavy impacts. Even if the hand is clenched on the fall and the person strikes the ground with the hand clenched, injuries can arise resulting in joint and skeletal injuries in the hand or the fingers. The reason is that the cavity which is formed within the hand when it is clenched allows the fingers, on external pressure, to be displaced further in against the centre of the clenched hand.